Various applications require boats to be moved to and from a support frame and a body water.
For example road going trailers are commonly used to transport boats overland and to store boats away from a body of water. Boat trailers allow a wide range of different sizes of water vessels to be deployed to and retrieved from bodies of water.
Relatively simple boat trailers rely on the trailer being backed down a boat ramp and partially submerging the trailer. This then allows a boat to be pushed off the trailer with the assistance of a number of passive roller elements. When the boat is to be retrieved it must be accurately aligned with the trailer to allow a winch system to be used to pull the boat back over the trailer rollers.
Winch based retrieval systems are difficult for some users to employ effectively, while also requiring the boat and the trailer to be precisely aligned with the winch rope secured to a strong point at the bow of the boat. Furthermore, the loading of boat trailers with winches will normally result in the boat user getting wet.
Winch based systems—whether they be manually cranked or driven by an electric motor—are also relatively slow. It is not uncommon for winching operations to take five or more minutes to load a boat depending on boat ramp angle. Gearing systems are also employed with winches used to retrieve relatively heavy boats, allowing the winch to a load the boat but at the cost of significantly slower loading speeds.
Boat trailers must also be at least partially submerged for relatively long periods to allow for winch based loading operations. This approach will expose the trailer frame and its associated components to water (and frequently saltwater) which can damage the trailer components. Salt water exposure in particular is very common for boat trailers and has a highly corrosive effect on metal components.
Attempts have been made to address these issues through providing boat loading systems which incorporate powered loading rollers.
For example, US patent specification U.S. Pat. No. 4,363,590 discloses the provision of an electric motor mounted to the rear of a boat trailer frame. This motor is connected to a rear mounted powered roller system via a system of drive shafts and gears. The electric motor rotates the roller system to launch a boat from the trailer or to retrieve a boat which has had its bow pushed up into contact with the powered rollers.
Although improving on winch based loading operations the approach described by U.S. Pat. No. 4,363,590 normally ends up submerging the electric motor used in water, and salt water in many cases. This approach can drastically shorten the useful lifespan of the electric motor and will promote accelerated metallic corrosion of the drive system components.
Furthermore the active or working components of this loading system are difficult to access for repair and maintenance operations. These problems are aggravated by this loading systems use of a relatively complicated power transmission system which again must be maintained regularly to ensure effective and reliable operation of the device.
An alternative powered roller based loading system is disclosed in the applicant's own PCT patent specification, published as WO2013/191570. This document discloses the provision of a number of powered rollers mounted to the rear of a boat trailer, with rotation of the rollers being driven by a hydraulic, pneumatic or electric motors mounted to the outside end of each powered roller.
Although positioning the motor used in an accessible location, the powered roller loading system disclosed in this document causes problems when a variety of boats with different hull shapes and designs are to be loaded. Depending on the hull chine shape involved there is the potential for the upper sections of the hull to impact against the powered roller drive motor as the boat is drawn on to the trailer.
In addition to needing to accommodate various hull chine shapes a boat frame loading and unloading systems must also accommodate hull design features such as planing or lifting lines and lifting strakes. These features are provided in various configurations and dimensions to assist in lifting the hull in the water when underway.
Lifting strakes are usually accommodated by providing a soft deformable covering material over the trailer rollers to prevent damage to the hull as is drawn on to or off the trailer. However this approach is not particularly effective as the lifting strakes create a local point load on the roller which compresses the cover material and can still allow hull damage to occur.
The applicant's own PCT patent specification publication WO2013191570 also attempts to address this problem in a limited fashion with a set of static roller positions capable of flexing to a limited degree. Although more effective than just deploying a deformable cover roller material, this approach is still only effective for a limited number of hull design configurations.
A similar set of operational constraints and performance issues are also experienced with other forms of boat loading and unloading systems.
For example dry dock facilities are used to retrieve boats from bodies of water, generally for the purposes of repairs and maintenance. Dry docks can rely on water locks and large water pumping systems or alternatively submergible support frames which run up and down boat loading ramps. Invariably the components used in the implementation of a dry dock require a significant financial investment.
Smaller scale dock facilities are also desirable in boat house facilities which in practice function as garages for boats formed as standalone structures or as part of shorefront houses. It is common for a lifting cradle to be used in these applications, where a support frame is submerged and then lifted up underneath a boat driven into the house. These submergible frames are relatively large complicated pieces of equipment which must be precisely aligned with a boat before it can be lifted from the water by a high power drive system.
Drive on pontoon dock based facilities are also used to remove small and medium size boats from bodies of water. These systems consist of floating platforms tethered to static sites and provide an upper deck surface which a vessel can force its way on to as its bow depresses the leading edge of the dock. Although providing a portable lightweight loading system for a static location, these systems provide little control to the user during loading operations. The user must force their boat up onto the floating deck of the dock using the power of their own boat only—with too fast an approach resulting in overshooting the deck and significant damage to the boat.
In some instances there is also the need to launch and retrieve a boat from a larger water vessel which acts as a mother ship. For example large luxury water craft—commonly known as ‘super yachts’—can be used to launch and retrieve a variety of smaller water vessels such as smaller power boats, jet skis or tender vessels.
Again in these applications some form of boat support frame needs to be loaded and unloaded, with the problems discussed above being aggravated by the support frame also moving around on the surface of the water while a boat is to be loaded. In such applications it is advantageous to load a boat as quickly as possible while avoiding the use of winch systems which could be potentially dangerous to their users.
It would therefore be of advantage to have improvements over the prior art which addressed the above issues or at least provided the public with an alternative choice. In particular, it would be of advantage to have a fast usable boat loading and unloading system capable of working with a wide range of sizes and weights of boats. A boat loading and unloading system with a robust design which protected its active components from damage and water exposure would also be of advantage, as would a system with flexible operational characteristics capable of working a variety of hull designs without damage.